trackball

They walk among us, unseen by polite society. They seem ordinary enough on the outside but they hide a dark secret – sitting beside their keyboards are trackballs instead of mice. We know, it’s hard to believe, but that’s the wacky world we live in these days.

But we here at Hackaday don’t judge based on alternate input lifestyles, and we quite like this billiard ball trackball mouse. A trackball aficionado, [Adam Haile] spotted a billiard ball trackball in a movie and couldn’t resist the urge to make one of his own, but better. He was hoping for a drop-in solution using an off-the-shelf trackball, but alas, finding one with the needed features that fit a standard American 2-1/4″ (57.3 mm) billiard ball. Besides, he’s in the thumb control camp, and most trackballs that even come close to fitting a billiard ball are designed to be fiddled with the fingers.

So he started from the ground up – almost. A 1980s arcade-style trackball – think Centipede or Missile Command – made reinventing the trackball mechanism unnecessary, and was already billiard ball compatible. [Adam] 3D-printed a case that perfectly fit his hand, with the ball right under his thumb and arcade buttons poised directly below his fingers. A palm swell rises up to position the hand naturally and give it support. The case, which contains a Teensy to translate the encoder signals into USB commands, is a bit on the large side, but that’s to be expected for a trackball.

What do you do when you’re into trackball mice, but nothing out there is affordable or meets all your murine needs? You build one, of course. And if you’re like [Dangerously Explosive], who has a bunch of old optical mice squeaking around the shop, you can mix and match them to build the perfect one.

The mouse, which looks frozen mid-transformation into a rodential assassin, is a customized work of utilitarian art. Despite the excellent results, this project was not without its traps. [Dangerously] got really far into the build before discovering the USB interface chip was dead. Then he tried to sculpt a base out of Plasticine and discovered he’d bought the one kind of clay that can’t be baked. After trying his hand at making homemade salt dough, he painstakingly whittled a base from scrap pine using a drill and a hacksaw.

Every bit of this mouse is made from recycled bits, which, if you pair that with the paint job and the chosen shade of blinkenlights, makes this a green mouse on three levels. One of the two parts of this mouse that isn’t literally green, the cord, is still ecologically sound. [Dangerously] wanted a really long tail, so he scavenged a charger cable built for fruity hardware and threaded it through a hollowed-out piece of purple paracord.

We love the thumb-adjacent scroll wheel and the trackball itself, which is a ping pong ball painted black. The cool part is the guide it rolls around in. [Dangerously] spent a long time hand-whittling the perfect size hole in a particularly wide mouse palm rest. All that plastic shaving paid off, because the action is smooth as Velveeta.

The question of whether to use a mouse versus a trackball is something of a Holy War on the level of Vi versus Emacs. We at Hackaday want no part of such things, use whatever you want, and leave us out of it. But we will go as far as to say that Team Trackball seems to take things mighty seriously. We’ve never met a casual trackball user: if they’ve got a trackball on their desk then get ready to hear all about it.

[LayeredDesigns] mentions that all the free room inside the shell for this two-button modification has got him thinking of what else he could fit in there. The logical choice is a Teensy emulating a USB HID device, which could allow for all sorts of cool programmable input possibilities. One potential feature he mentioned was adding a scroll wheel, which the Teensy could easily interface with and present to the operating system.

Because nothing says “fun for kids” like barbed wire and hypodermic needles, here’s an interactive real-world game that everyone can enjoy. Think of it as a kinder, gentler version of Robot Wars, where the object of the game is to pop the balloon on the other player’s robot before yours get popped. Sounds simple, but the simple games are often the most engaging, and that sure seems to be the case here.

The current incarnation of “Bubble Blast” stems from a project [Niklas Roy] undertook for a festival in Tunisia in 2017. That first version used heavily hacked toy RC cars controlled with arcade joysticks. It was a big hit with the crowd, so [Niklas] built a second version for another festival, and incorporated lessons learned from version 1.0. The new robots are built from scratch from 3D-printed parts. Two motors drive each bot, with remote control provided by a 433-MHz transceiver module. The UI was greatly improved with big trackballs, also scratch built. The game field was expanded and extra obstacles were added, including a barbed wire border as a hazard to the festooned bots. And just for fun, [Niklas] added a bubble machine, also built from scratch.

The game looks like a ton of fun, and seems like one of those things you’ve got to shoo the adults away from so the kids can enjoy it too. But if you need more gore from your robot deathmatch than a limp balloon, here’s a tabletop robot war that’s sure to please.

[Madox] is a trackball user, which is fine; we at Hackaday respect and appreciate those who live alternative lifestyles. As you would expect, there aren’t many makes and models of trackballs being sold, and [Madox] wanted something ergonomic. A DIY solution was necessary, but how to you model something ‘ergonomic’ before printing it out? Floam, apparently.

Highly advanced 3D prototyping skills

Floam is a sticky, moldable goo originally sold as the follow-up to Nickelodeon’s Gak in the early 1990s. It consists of styrofoam pellets held together with a colored binder that doesn’t leave a mess and doesn’t dry out. While the Nickelodeon version is lost to the sands of time, a Floam-like substance is available at any toy store. [Madox] picked up a few blister packs and began modeling his ideal trackball.

With the proper shape in hand, [Madox] needed a way to get this design into a computer. Photogrammetry is the solution, and while earlier experiments with Autodesk Catch were successful, Autodesk has morphed and rebranded their photogrammetry software into Autodesk ReMake. Turing a pile of styrofoam balls into a 3D model is as simple as taking a bunch of pictures and uploaded to Autodesk’s ‘cloud’ service.

In just a few minutes, a proper 3D mesh arrived from the Autodesk mothership, and [Madox] took to importing this model into Fusion 360, fiddling with chamfers, and eventually got to the point where a 3D printer was necessary. It took a few revisions, but now [Madox] has a custom designed trackball that was perfectly ergonomic.

There were some truly bizarre computer keyboards in the 1980s and 90s. The Maltron keyboard was a mass of injection-molded plastic with two deep dishes for all the keys. The Kinesis Advantage keyboard was likewise weird, placing the keys on the inside of a hemisphere. This was a magical time for experimentations on human-computer physical interaction, the likes of which we haven’t seen since.

Now, though, we have 3D printers, easy to use microcontrollers, and Digikey. We can make our own keyboards, and make them in any shape we want. That’s what [Andrey]’s doing. The 32XE is an ergonomic keyboard and trackball combo made for both hands.

The keyboard has curved palm rests, a trackball under the right thumb, and is powered by the ever popular DIY mechanical keyboard microcontroller, the Teensy 2.0. This keyboard is equipped with a trackball, and that means [Andrey] needed a bit of extra electronics to handle that. The mouse/trackball sensor is built around the ADNS-9800 laser motion sensor conveniently available on Tindie. This laser mouse breakout board is built into the bottom of the keyboard, with enough space above it to hold a trackball… ball.

Since this is a very strange and completely custom keyboard, normal mechanical keyboard keycaps are out of the question. Instead, [Andrey] 3D printed his own keycaps on an FDM printer. Printing keyboard keycaps on a filament-based printer is extremely difficult — the tolerances for the connector between the switch and cap are tiny, and nearly at the limit of the resolution of a desktop filament printer. [Andrey] is taking it even further with inlaid keyboard legends. He’s created a keycap set with two color legends on two sides of the keycaps. If you’ve ever wanted to print keycaps on a 3D printer, this is a project to study.

[Evan] always wanted a trackball for his arcade cabinet. It’s hard to play Missile Command with anything else, and Centipede with any other controller is just stupid. So he bought one, jury-rigged a mounting bracket for it, and then fried it by plugging the wiring harness in backwards. Doh!

But proving Edison’s famous statement that innovation is 1% inspiration and 99% having the right stuff in your junk bin, [Evan] dug deep and came out with one of twenty (!) old ball mice that he had purchased for just such an occasion. (Yeah, right.) Since a ball mouse is essentially an upside-down trackball, all that remained for him to do was reverse-engineer the mouse and swap its controller in for the busted trackball.

A simple hack, born of necessity, and well done. If you’re stuck with a crate of optical mice instead, consider turning them instead into optical laser rangefinders.